Pressure-fluid motor



Nov. 11', 1930. E. H. SHAFF PRESSURE FLUID MOTOR Filed oct. 1s, 1924 3 Sheets-Sheet lV .fil

, @N H Y n Y 141 @m LI A S Nm v MI l Nov. 11,' 1930. E. H. sHAFF I PRESSURE FLID MOTOR 'Filed oct. 1s, 1924 5 Sheets-Sheet 2 WML Nqv. 11, 1930.

E. H. vsHAFr:

PRESSURE FLUID 'KOTOR Filed oct. 1:5, 1924v 3 Sheets-Sheet 3 Egg.

Patented Nov. 1.1, 1930 UNITED STATES PATENT oFFlc/E `Emrrsr H. sHAIr, or GRAND HAVEN, MIcHrGAv, AssIGNoB. 'ro' wir. n. KELLER, ING.,

0F GRAND HAVEN, MICHIGAN, A. CORPORATION 0F MICHIGAN rnEssUnn-FLUID Moron.

Application mea october 13, 1924. semi 110.743,205. i

The invention has eneral reference to a av rotational'movement to the shaft or spindle of a portable tool.

Pressure fluid motors of the rotary type have been the subject of considerable eHort in an attempt to produce a motor adapted `for portable tools and capable of withstanding long and hard'usage. As a result, ro.- tary pneumatic motors of various forms have been produced, some of which embody an ordinary crank shaft for converting reciprocatory 'motion intol rotary motion; while d others have embodied two coacting members inclined with respect to the direction of the reciprocatory movement and sliding relative to each other.y The former or crank type is inmany instances objectionable for the reason that it must necessarily occu y a sub- .stantialamount of space because o its cumbersome character. Also, in this type, considerable side pressure of the pistons on the cylinder walls results from the fact that the connecting rod must swing sidewise a disf A tance equal to the length of the stroke. The

other type hasmproven objectionable because of the excessive amount of friction developed between the sliding parts. To over-- vreferred to, while obtaining. eiliciency in,

power transmission, with compactness of the parts, is the primary object oi' my invention.

Among the salient it'eatures` of my -improved motor is the use of a plurality of bell-cranks arranged in circular series so as to be successively actuated by a series of motor units correspondingly arranged. Another feature of importance is the utilization .of a single crank pin as a lever arm common to each of the bell-cranks of the rotary series. Said pin has associated therewith on the one hand'a plate disposed perpendicularly to the axisof the pin and inclined relative to the direction of reciprocation pro- `isrof a thoroughly -tached and illustrating its construction,

duced bythe several motor units; whereby,- i

by the successive application of power by said units to spaced pointsin the periphery of the Slate, the pin is 'ven a gyratory motion. n 'the other han the pin is connected to a crank arm upon a tool spindle or other shaft so that the pin results in a rotation of the shaft. l

A general object of the invention is to produce a construction or the motor, which ractical character capable of being manuiactured at a relatively low cost and yet strong andvdurable in character.I v

In. the accompanying drawings I have shown my invention as applied to a portable grinding tool but it will be understood that the invention is not limited to portable tools but is susceptible of general application. Also it is contemplated that variouschanges in the construction and arrangement of the parts illustrated and hereinafter fully described may be varied by those sln'lled 1n the art without departing from the spirit and scope of the invention as expressed in the appended claims.

' Figure 1 of the drawings is a longitudinal4 central sectional `view through a portable grinder embodying my invention.

Fig. 1a is a perspective view illustrating the operation of the power transmission employed. I l Figs. 2 and 3 are transverse sectional views on enlarged scales taken approximately in the `lplanes of lines 2 2 and 3 3 respectively of Fig. 1. v

Fig. 4 is a view of the major portion of the power transmission detached from the motor casing.

Fig. 5is a transverse sectional view on an enlarged scale taken approximatelyin the plane of line 5-5 of Fig. 1.

Fig. 6 isla rear view of the crank plate degyrator'y motion of the 25 mitted b V 7 is a sectional 'view throu h the plate"v ta'ken in the plane of line 7-7 Fi 6.

Fi 8 is a sectional view through t e valve mem er taken in thei plane of line 8-,8 of

General description .Referring first to Fi 1 of the-drawings,

f 10 designates the annu ar casing of a port 10 abley grlnder comprising a main or rear section 11 and a front section 12. The rear sec' tionI is closed by means of a late 13 with I which is rigid a handle 14\. -1thin the rear or main section of the casing is a plurallty of 15 motor units arranged in circular 'series and each comprlsmg a cylinder 15 and a pistonf 16. The flow of fluid pressure to and from these several motor units is controlled by an automatically operating valve mechanism enerally designated by the numeral 17, rand ya manually operable valve in the handle enerally designated by the numeral 18. ower impulses imparted tothe pistonsof the several motor units are successively trans.-

bell-cra s arran ed in circular series and formed by a cran plate 20 an`d a crank pin 21, said pin constituting in effect an arm common toeach of the series of `bell-cranks,

`3o the other arms bein embodied in the plate' 20. 'The crank s arm 22 rigid wit the tool spindle 23, which in 1s`connected to a crank is journaled in the forward section 12 of the casing, and the plate 20 has a slidin bearing near its center on a plate rigid with the arm 22 and providing in effect a shifting fulcrum, continuously moving with Athe crank pin, for each `of the bell-cranks. l L The invention in detail '.lhe main or rear section 11 ofthe tool casing is annular in form, and inthe present inf stance is cast to form integral therewith a cylinder block 24 which is boredto receive sleeves forming a circular series of cylinders is bell-shaped at its rear/end anl is shaped at this end to interengage with the forward end of the main casing 11. The two-'sections are secured together by means of afseries of bolts 25 entered thnough the rear plate 13 and .be-

tween the adjacent'icylinder blocks (Fig. 3) ,i their forward ends being anchored in lugs -26l formed integral with the casing section 12.

The bolts 25 also serve to secure the'rear plate y 13 in place..

' Formed integral with the rear plate 13 of the casing is arearwardly extending tubular portion 27 constituting a hub for the valve mechanism 17 and providing a support to -66 which the handle v14 may be secured,V the piston rodsv 19 to a plurality ofpreferred con-- mesmo handle being in this instance shown as formed integral with the portion 27.

The Valvemechanism 17 which rI by preference employ` com rises va stationary casing 28 havin aserieso circumferentially arranged slots' orming ports 29 which communicate\ with -passages 39 formed in enlargements 40 integral with the plate 13.. Figs. 1 and 5). The passages 39 are incline forwardly and outwardly and at their forward ends 4open into the rear ends of the cylinders15. Within the valve casing l28 isarotary valve member 41 havin at its rear end an 'annular groove 42 from which a plurality' of port holes 43 (Figs. 1 and 8) extend forwardly and terminate in a transverse slot 44 formed on the eriphery of the valve member and ositione l approximately centrally thereo so as to register successively with the ports 29. The valve member also has a central bore 45 opening at its forward end into a transverse slot 46l located diametricall'y opposite the slot 44 and also adapted to register successivel with the ports 29. The annular groove 42 ig. 1) communicates at all times with a passage 47 in the handle to which motive fluid is supplied under` the control of the manually-oper-k able valve 18; Iso that in the rotation of the valve member,`pressurel is admitted successively to the circular fseries of" ports 29 byl way of the holes or ducts 43 and the transverse slot'44. On the other hand the bore 45 communicates at its rear end/with an exhaust passage 48 extending radially outwardly into an exhaust chamber 49- which is o-pen to the atmosphere; so that as the slot 46 registers successively with the ports 29' communication is established between the cylinders and the atmosphere.

The manually operable Valve herein shown is of ordinary construction so that it, is ldeemed unnecessary to describe it in detail.

It lcomprises generally a valve member'() which is operable by a lever51 against the actiony of a spring 52 to control the passage of motive fluid through ports 53 and 54 in a'valve casing 55,'the port 53 being in com-v munic tion with a source of ymotive fluid supply and the port 54v with thepassage 47.

The piston rods 19 connect the pistons 16 (with. the crank plate 20 so that power impulses produced by the several motor units lare. transmitted to the plate 20 to imparta gy'fra-l tory motion to the crank pin 21 as hereinafter morefully described. The rods 19 are -herein shown as connected at their rear ends Nto the l pistons byfmeans of balls 56 and socket members 57 secured as by means of rivets to the rear end walls ofthe pistons. The forward ends of the rods are secured to thev plate 20by meansof balls 58 seated in sockets 59 formed in spaced relation .about the periphery of the plate 20,x and secured in said sockets by means of a retaining plate 60 (Fig.v2).

rigid wit the pinf Herein the hub portion` Athe late 2O as' by'means of screws 61.'

e plate 20 is made rigid with the crank pin 21 by securing it upon abearmg plate 62 havin l a central hub (i4-which is I1n' turn 64 is shown as screw-threaded upon the pin 21, the two parts being secured .by means of a lock nut 66.- l

.For the purpose of rotating the. valve Amember 41, the crank pin 21 is inthe present instance drilled axially thereof to receive an inclined stem 65 formed integral with ashaft 67 disposed axially of the casing andjournaled in a sleeve 68 which in turn is mounted in the cylinder block. Said shaft has at its forward end a head 69 having an inclined face from which the stem 65 projects. A hardened thrust washer 7 0 has a bearing on said inclined face and in turn provides a bearing for the sleeve 65 and the `hub vportion 64 of the plate 62. The opposite end of the shaft 67 has a clutch connection with the* forward endy of the valve member 41. Said clutch connection in the present instance comprises registering slots 71 and 71a in the rear end of the shaft 67 and in the forward end of the valve member,'and a key 72 adapted to enter into said slots.- I have shown two pairs of slots 71a in the valve member'so arranged as to change the relative positions Y of'the valve depending upon the direction of rotation desired.

The crank plate 20 is operated upon bythe several motor units to effect a wabbling mo- 4tion which is transmitted to the crank pin to cause it to rate in a path such that it 'de-A scribes in e ect a cone having lits apex disposed coaXially of the shaft 67. To hold the plate 20 against rotation and at the same time permit of this wabbling motion, it is provided centrally thereof with a series of gear teeth 73 constituting a bevel pinion;y and this gear meshes with a stationary gear 74 rigid with and 'in thev present instance formed integral with the forward end of the stationary -sleeve 68. The gear 74 has diametrically opposite clutch vteeth 74a (Figs. 2 and 4) which engage in grooves 74b in the forward end of the cylinder block to hold the gear against rotation. /The gear 73 is in ther present instance also formed integra-l with its plate 29, the latter being made of sheet metal and shaped near its center to form the teeth of said gear 73 as shofwn clearly in Fig. 6. A thrust washer 75 is interposed between the head 69 on the shaft 67 and the mitted to the spindle to rotate it will now be described. It comprises the crank arm 22 rigid with the spindle 23 at the rear end of the latter. Said arm is also inclined relative vto the axis Aof the'shaft 67 so as to lie perpendicular to the .axis of the crank pin 21. Rigid with the ar 22 but spacedrearwardly there'- .from is b ring rinlg "77 which encireles the hub portion 64 of t v 22 is apertured at its free end to receive the end of the crank pin, and radial thrust ball bearings 78 are interposed between the pin e plate 62. The arn4v 70 andthe arm, the pin being provided with an annular groove 79 to rform a race-way fonthe balls. Similarly, ball thrust bearings 80 are interposed betweenl the ring) member 77 andA the plate 62, a-ball race 81 eing formed between the plate 62 `and its hub portion 64.

By this construct-ion the crank arm 22 is free to revolve about the pin 21 as the latter describes its gyratory motion under the successive impulses of the pistons.l 82 designates a pair of oilholes through the pin`21 to supply lubricant from the interior of the casing to the stem 65. v

The crank arm 22 is rotatably mounted in the forward casing section 12 through the medium of a ball vbearing having inner and outer race-ways 83l and 84 securedv respec-y tively-to a hub portion 85 of the arm and to the casing 12. The hub -portion is securedL upon a reduced rear end portion 86 ofI the spindle as by. means of akey 87 The arm 22 and ring member 77 are integrally connected by a part 88 formed diametrically opposite said members so as to eect a counterbalancin action thereon.

I`he casing secti spindle 23 is reduced in diameter to provide at one end a bearing for the rear end of the spindle 23 and at its forward end a bearing for the forward end of the spindle. vThe latter bearing is similar to'that described in connection to the rear end. It'is generally designated by the numeral 89. In the eX- treme forward end of the casing lsection 12 I provide, a plug 90 between which and the bearing 89 is interposed asuitable packing material 9.1.'

The forward end of thespindle is provided with a pair of clamping plates 92 between which a grinding wheellmay be secured, the

on 12 where it encricles the l spindle being provided with a clamping nut 93 for this purpose. 94 designates a-housing mounted on the forward end of the casing and serving partially to enclose the grinding wheel.

To permit of the esca e from theinterior of the casing of motive. uid leaking past the pistons into the casing, I provide a passage formed by a duct 95 in the stem 65 and eX- `tending longitudinally through the said stem and opening at its rear end into a bore 96 through the shaft 67. Radial ports 97 connect the rear end of the bore 96 with a chamber 98 which communicates with t-he atmosphere througha duct 99 in the cylinder block. The motive fluid in its passage serves to conduct heat from the parts.

1o- Figsl, 4 and 5, and assuming the arts to be f haust and the other two units are also ex L hausting. It will thus be observed that'there of motive fluid than when' this slot is of large bis ` through the ducts 43 to the slot 44.

1D0-is a plug screw-threaded into the forward ycasing section 12, which is removable to permit ofthe introduction oflubricant into the casing. 101 is a ball valve in the handle, seated on anA air inlet port v102 in a fitting 103, to permit ofthe passage of air to the motor when the motive supply is cut oif by the operator, thus enabling the motor to continue to operate under momentum.

The operation is as follows: Referring to in the position shown, ressure uid is admitted to the ,valve nec anism throu h the operation of the manuallyoperable va ve 18, and 'passes around the annular' oove 42 evalve membery in the position assumedtFig. 5) has previously established communication be-` -tween the slot 44 'and the port 29 leading to the upper left motor unit, and is commencing. t0 uncover the port leading to the upper unit.

Also the valve member is uncovering the port leading to the lower left unit and establishin communication between such unit and the ex aust slot 46. Thefupper and lower right units are also in communication with the exhaust slot 46 through the several ports 29.

Accordin 1 the up rleft unit has artiall y Pe P y complete its power stroke (Fig. 4) the upper unit is just commencing its power stroke; the lower left unit is just commencing to ex'- 4to admit motive fluid to and from the motor units. I have found in practice/that by making the inlet slot 44 in the valve member very narrow greatly increases the speed of operation ofthe tol with a lower consumption size. This result I attribute to lthe restriction of the air in its passage between the ducts 43 on the one hand and the port 29 and passagel 39 on the other, producing in eifect an increased. velocity of the air and impact thereof against the pistons.

los

lThe impulses which are' thus produced in rapidsuccession by the several motor units aretransmitted by their'respective. pistons' to the crank plate 20, which it will be remembered is held against relative rotary movement by the intermes'hing gears 7-3 and 74. The crank plate, in turn bears upon the ring 77 through the thrust bearings 80. Thus, the

4the rotary motion is relative sliding motion etween the wabbling vposes of repair.

latter provide, in effect a shifting fulcrum for the series of vbell-crank levers, one arm of each of which is formed b the plate 2O and the other arm of which is ormed by the crank in 21'. Accordingly each impulse imparte to the plate produces in the crank pin a swin ing motion; andassuch impulses occur 1n rapid succession about the periphery of the platev the swinging movements produced comine to impart a lgyratory motion to the crank pinv in which it describes a circular path defining in eifect a cone having its apex coincident with the axis of thecrank plate.

y The .gyratory motion thus imparted to the crank pin is transmitted to the crank arm 22 through the radial thrust ball bearings (8, with the result that rotary motion is produced in the lspindle 23 which is rigid with the arm. Because thediameters of both bearings 7 8 "and '80 are relatively small, their ripheral speeds are correspondingly small. his is ofgreat importance as will be evi-v dent 'from the fact that these tools operate at a speed of about 3500 revolutions per minute.

It will be apparent that by the construction and arrangement which I have thus provided I- -have substantially eliminated the friction which is necessarily present in the prior motors of this general type in which roduced solely by a member and anA inclined plate rigid with or connected to the tool spindle. f Thus I have obtained certain advantages in a tool 'of the type in which reciprocatory motion is 'con- 'verted into rotary motion through the medium ofa crankshaft, and have not sacrificed compactness in construction. I have found v in practice that the motor when constructed in accordance with my invention is'substantlally more ydurable than those of thel sliding ty e above referred to.

oreover,it will be seen that the construction employed is relativel simple; also that the scctlonal connection o the casing and the manner in which the several mechanisms are detachably secured together renders it possible readily to disassemble the tool for pur- I claim is my invention:

1. A pressure luidmotor of the character described comprising, in combination, a crank arm, a wobbler comprising an inclined pressure plate and an axially pro] ecting stem,- said crank arm being apertured to receive said axial stem, and two `sets of antifriction elements interposed between the crank arm respective sets disposed on opposite faces of said crank arm so as to. hold the wobbler and crank againstrelative axial movement, said stem being adjustable axially relative to the plate to permit of the insertion or removal of the anti-friction elements. 2. A pressure fluid motor,l comprising, in

and said axial stem withthe elements of the .l

combination, a crank arm, a wobbler comprising an inclined .plate having an axial stem, said crank arm having'a pair of spaced parallel members apertured to receive said 5 stem, two sets of anti-friction elements interposed between said stem and said crank members with the elements of the respective sets` disposed on opposite' faces-of the crank arm, said'stem being screw-threaded in said D plate so as to be adjustable ina direction axially of the plate to permit of the insertion' or removal of the bearing elements, and a lock Ibiut on the stem between the two crank mem` ers. 5 In testimony whereof, I have hereunto afxed my signature. ERNEST H. SHAFF. 

